1. Field of the Invention
The present invention relates generally to the field of snorkels and more specifically to an improved dry top for snorkels.
2. Background Art
This invention is an improvement of the snorkel dry top disclosed in issued U.S. Pat. No. 6,994,085 to Chih-Cheng Shiue and assigned to the assignee hereof. Snorkel dry tops comprise devices configured to prevent water from entering the open top of a snorkel tube. Typically they include a rubber-like diaphragm and a float or buoyant device. The diaphragm is positioned in proximity to the top opening for relative movement thereto for opening and closing the opening. Movement of the diaphragm is controlled by the float and its response to whether the water level is sufficiently high on the snorkel to make the float buoyant. When the float is immersed, its buoyancy forces it toward the top opening thereby forcing the diaphragm to close the opening and prevent the entry of water into the snorkel tube. When the float is above the water, gravity forces the float away from the opening, pulling the diaphragm from the opening as well and thereby allowing air to pass freely into and out of the snorkel tube. Some such snorkel dry tops also provide splashguards to resist entry of water droplets while the snorkel top is above the water surface and the diaphragm is pulled away from the opening. Such droplets of water come from splashing waves and the like and can otherwise enter the open top even while the top of the snorkel is above the water surface. One such snorkel dry top is described in U.S. Pat. No. 6,994,085 and includes both a diaphragm and float assembly as well as a splashguard referred to therein as a mask. Other such dry tops are disclosed in issued U.S. Patents such as U.S. Pat. No. 5,960,791 to Winefordner et al and U.S. Pat. Nos. 6,904,910 and 7,077,127 to Christianson.
An inherent problem associated with snorkel dry tops that depend on a combination of buoyancy and gravity is that they're subject to inappropriate operation when they're tilted above the surface. When they're above the surface, gravity should keep the tube top open so that air can pass freely into and out of the snorkel. However, if the top is tilted, the effect of gravity can inadvertently close the opening by forcing the diaphragm against the opening, thereby preventing the free-flow of air into and out of the snorkel tube. Even a rather modest tilting of the snorkel combined with a suction effect of air rushing into the opening while the snorkeler is breathing in, can inadvertently close the opening at an inappropriate time and thereby interfere with normal operation of the snorkel.
Therefore, there is a need to improve such dry top snorkels by configuring them so that they are more likely to stay open while they're above the water surface even when they are tilted.